Sydney Foster, haunted by guilt after a fatal accident, drives three thousand miles across the continent on a slight hope that in the solitude of what was once her grandmother's house on Ponokanet, a small pine-capped island in Cape Cod Bay, she might discover a new way to be in this world. But solitude proves hard to find, even there. Her mother, alienated by years of argument, arrives on the island just hours behind Sydney. A stranger - the island's caretaker - lives now in the old barn. Yet Sydney must stay. She must trust that Ponokanet is the medicine she needs. It is Ponokanet and the enormous boulder standing watch at the island's rim that evoke the past, linking Sydney to four bold women who came before her. With vivid setting and strong willful characters, their story weaves forward through centuries to the present day, to Sydney Foster as she confronts new truths and digs inside to reclaim a stronger self.